Castleton is a civil parish in the English county of Dorset. The parish virtually encircles the town of Sherborne, and contains within its boundary both Sherborne Castle and Sherborne Old Castle. These and other buildings within the parish are today generally regarded as comprising part of Sherborne. The parish includes the hamlets of Wyke, Silverlake, Over Coombe, Higher Clatcombe, Dodds Cross, and Pinford. In the 2011 census the parish had a population of 155.